I don't think this is the strongest argument. Every technological revolution so far has initially benefited the wealthy and taken a generation or two for its effects to lift the masses out of previous levels of poverty, but ultimately each one has.

To me the stronger argument about AI is that this revolution won't. And that's because this one is not really about productivity or even about capital investment in things that people nominally would want (faster transport, cheaper cotton, home computers). This one is about ending revolution once and for all; it's not about increeasing the wealth of the wealthy, it's about being the first to arrive at AGI and thus cementing that wealth disparity for all perpetuity. It's the endgame.

I don't know if that's true, but that's to me the argument as to why this one is exceptional and why the capitalist argument for American prosperity is inapplicable in this case.

I don't know about for all perpetuity. If history has shown, anyone that reaches the pinnacle eventually becomes complacent, technology improves by becoming faster/cheaper/smaller. That just means it is prime to always be susceptible to a new something coming along that stands on the shoulders of what came before without having to pay for it. They start where the current leader fought to achieve.

We have had the capacity to have zero poverty for many decades, maybe over a century. China eliminated extreme poverty.